The present invention relates to an air quality system for use in a vehicle. In particular, the present invention relates to the air quality system being used to control the air quality within a cabin of the vehicle.
Conventional air quality systems for vehicles are typically utilized to control air quality within a cabin of the vehicle by controlling a source of the air flowing into the cabin. Such a system typically comprises an outside air quality sensor for detecting an air quality parameter such as carbon monoxide, nitrous oxides, and the like. A controller is responsive to the outside air quality sensor to determine a current value of the air quality parameter that is detected.
The controller then makes a determination as to whether the air quality within the cabin is better or worse than the air quality outside of the cabin. Once the determination is made, the controller controls airflow into the cabin by controlling the source of the air. For instance, if the air quality within the cabin is better that the air quality outside of the cabin, then the air source will be the cabin, i.e. recirculated air. If the air quality outside of the cabin is better than the air quality inside the cabin; then the air source will be fresh air from the outside of the cabin.
In typical prior art systems, an air inlet valve is responsive to the controller and movable between recirculate air and fresh air positions such that fresh air from outside of the cabin moves through the air inlet valve into the cabin in the fresh air position and air from within the cabin is recirculated in the cabin in the recirculate position. Hence, once the determination of whether the air quality within the cabin is better or worse than the air quality outside of the cabin, the controller actuates the air inlet valve to move to either the recirculate air or fresh air positions.
One example of a prior art air quality system is shown in U.S. Pat. No. 5,259,813 to Abthoff et al., granted on Nov. 9, 1993. The air quality system of Abthoff et al. is utilized to control the air quality within a cabin of a vehicle. The system comprises an outside air quality sensor for detecting an air quality parameter outside of the cabin of the vehicle. A controller is responsive to the outside air quality sensor to determine a current value of the air quality parameter that is detected. The controller then calculates the air quality within the cabin based on pollutant concentrations in the air outside of the cabin. Such a calculation takes into account time-varying concentrations of the pollutant in the air outside of the cabin and the pollutants measured. It should be noted that an air quality sensor is not used to determine the air quality within the cabin.
Still referring to Abthoff et al., once the air quality within the cabin is calculated, i.e., a concentration of the air quality parameter within the cabin is established, the controller makes a determination as to whether the air quality within the cabin is better or worse than the air quality outside of the cabin. The controller then controls airflow in the cabin by controlling the source of the air. For instance, if the air quality within the cabin is better that the air quality outside of the cabin, then the air source will be the cabin, i.e. recirculated air. If the air quality outside of the cabin is better than the air quality inside the cabin, then the air source will be fresh air from the outside of the cabin.
In Abthoff et al., an air inlet valve that is responsive to the controller is employed to move between recirculate air and fresh air positions such that fresh air from outside of the cabin moves through the air inlet valve into the cabin in the fresh air position and air from within the cabin is recirculated in the cabin in the recirculate position. Hence, once the determination of whether the air quality within the cabin is better or worse than the air quality outside of the cabin, the controller actuates the air inlet valve to move to either the recirculate air or fresh air positions.
Abthoff et al. further teaches the use of ventilation openings in a rear of the vehicle to create airflow through the cabin while the vehicle is moving. This airflow is to remove the air within the cabin. The ventilation openings are stand-alone features that are not integrated into the air quality system of Abthoff et al. Such conventional ventilation openings allow for slow rates of airflow through the cabin. Hence, when the air inlet valve is in the fresh air position to draw in fresh air from outside of the cabin, the rate for replacing the air within the cabin of the vehicle with the fresh air is slow. Therefore, there is a need in the art to provide a faster airflow rate through the cabin to quickly purge the air from the cabin and replace the air with fresh air from outside of the cabin.
The present invention provides an air quality system for controlling air quality within a cabin of a vehicle. The air quality system comprises an air quality sensor to detect an air quality parameter. A controller is responsive to the air quality sensor to determine a current value of the air quality parameter and determine whether the current value exceeds a predetermined limit. The predetermined limit represents poor air quality within the cabin. The controller is operable between purging and non-purging modes to purge the air from the cabin in the purging mode when the current value of the measured parameter exceeds the predetermined limit. An air inlet valve is responsive to the controller and movable between recirculate air and fresh air positions such that fresh air from outside of the cabin moves through the air inlet valve into the cabin in the fresh air position. The air,inlet valve moves to the fresh air position when the controller is in the purging mode to improve the air quality within the cabin of the vehicle. A cabin relief valve is responsive to the controller and movable between purge and recirculate positions such that the air within the cabin is discharged from the cabin to the outside of the cabin in the purge position. The cabin relief valve moves to the purge position when the controller is in the purging mode to improve the air quality within the cabin of the vehicle.
A method of controlling the air quality within the cabin of the vehicle is also provided. To start the method requires establishing the predetermined limit for the air quality parameter. A current value of the air quality parameter is then determined and compared to the predetermined limit for the air quality parameter. When the determined current value of the air quality parameter exceeds the predetermined limit for the air quality parameter, the air within the cabin of the vehicle is replaced with fresh air from outside the cabin of the vehicle thereby improving the air quality within the cabin of the vehicle.
The present invention provides several advantages over the prior art. The connectivity between the controller and the cabin relief valve allows the air quality system to quickly and efficiently replace the air in the cabin of the vehicle with fresh air from outside of the cabin of the vehicle. The ability of the controller to both move the air inlet valve to the fresh air position and the cabin relief valve to the purge position provides rapid replacement of the air within the cabin when the air within the cabin is of poor air quality.